Another exception is the Gotek drives. They don't take the motor flip-flop into account and are always on. [https://64nops.wordpress.com/2021/07/04/a-la-decouverte-du-fdc/ Source]
Some FDC commands don't require the motor to be on. For example, the seek or recalibrate commands that move the floppy drive head work fine with the motor off. And seek/recalibrate also work with an empty drive (ie. without a floppy disk inserted). [https://64nops.wordpress.com/2021/07/10/a-la-decouverte-du-fdc-episode-2/ Source]
The floppy disk rotates at a nominal speed of 300rpm, with some tolerance. This tolerance of the FDC has been measured by [[Roudoudou]] to be ±12% (it worked from 220 kbits/s to 283 kbits/s for a reference of 250 kbits/s). [https://64nops.wordpress.com/2021/09/02/a-la-decouverte-du-fdc-episode-4/ Source]
The FDC speed is more impressive when you realize the Amstrad CPC’s tape loads at only 2 kbits/s in fast mode. Note: tape loading can be way faster than that if an MP3 player is used instead of a real physical tape, as it has been demonstrated here: https://youtu.be/MAIsOIwgJWA
Note: Some FDC commands don't require the motor to be on. For example, the seek or recalibrate commands that move the floppy drive head work fine with the motor off. And seek/recalibrate also work with an empty drive (ie. without a floppy disk inserted). [https://64nops.wordpress.com/2021/07/10/a-la-decouverte-du-fdc-episode-2/ Source]
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